antagonist

noun

an·​tag·​o·​nist an-ˈta-gə-nist 

1

: one that contends with or opposes another : adversary, opponent

political antagonists

2

: an agent of physiological antagonism: such as

a

: a muscle that contracts with and limits the action of an agonist with which it is paired

called also antagonistic muscle

b

: a chemical that acts within the body to reduce the physiological activity of another chemical substance (such as an opiate)

especially : one that opposes the action on the nervous system of a drug or a substance occurring naturally in the body by combining with and blocking its nervous receptor compare agonist sense 2b

Did you know?

On the stage or screen, in a story or a novel, the protagonist is the main character and the antagonist is the opposing one. Pro- and ant- usually mark the good and bad characters, but not always; there may occasionally be an evil protagonist and a good antagonist. In the drama of the real world, it's especially hard to sort out which is which, so we usually speak of both parties to a conflict as antagonists. During a strike, for example, representatives of labor and management become antagonists; they often manage to antagonize each other, and the antagonism often remains after the strike is over.

Synonyms

• enemy
• opponent
• foe

Examples of antagonist in a Sentence

They are interested in character first, and in Don, a foul-mouthed psychopath with a hair-trigger temper and buried longings for Gal's wife, they have created a truly scary antagonist. —David Ansen, Newsweek, 18 June 2001

In the 1970s researchers discovered that the actions of estrogen and other hormones can be blocked chemically by drugs called hormone antagonists … —David Plotkin, Atlantic, June 1996

If the new comptroller is a true antagonist of the seamy bond market practices he decried in the campaign, why has he installed as his first deputy the public finance director from the Dinkins administration who was Holtzman's accomplice in each of those deals. —Wayne Barrett, Village Voice, March 1994

As in that film, Kopple not only draws an intimate portrait of the protagonists and antagonists in the strike, but also deftly locates the workers' struggle within a broad context of economic and political forces. —Frank Thompson, Film Comment, January/February 1991

please name the novel's hero and his antagonist

his antagonist in the boxing match

Recent Examples on the Web

The June 3 episode of Simmons’ video pod has put up some of the biggest numbers for his YouTube channel in recent months, as 270,158 users thus far have tuned in to watch the host quash a beef with Meadowlark Media star (and Mark Cuban antagonist) Pablo Torre. —Anthony Crupi, Sportico.com, 14 Oct. 2025

Iran, which has sought to portray itself as a key player in the Palestinian cause as Israel's primary antagonist, will be absent from the summit in Egypt, where Trump is now headed, despite receiving an invitation. —Shane Croucher, MSNBC Newsweek, 13 Oct. 2025

Kirk was seen as a particularly effective antagonist to campus leftism and to the progressive project as a whole. —Jeremy Lott, The Washington Examiner, 10 Oct. 2025

Bronstein, her every utterance brimming with deadpan passive-aggression, was shrewd to cast herself as one of Linda’s many antagonists. —Justin Chang, New Yorker, 9 Oct. 2025

Word History

Etymology

see antagonize

First Known Use

1555, in the meaning defined at sense 1

Rhymes for antagonist

• protagonist
• agonist

Kids Definition

antagonist

noun

an·​tag·​o·​nist an-ˈtag-ə-nəst 

: one that opposes another

Medical Definition

antagonist

noun

an·​tag·​o·​nist -nəst 

: an agent that acts in physiological opposition

contact between a tooth and its antagonist in the opposing jaw

: as

a

: a muscle that contracts with and limits the action of an agonist with which it is paired

called also antagonistic muscle

compare agonist sense 1, synergist sense 2

b

: a chemical that acts within the body to reduce the physiological activity of another chemical substance (as an opiate)

especially : one that opposes the action on the nervous system of a drug or a substance occurring naturally in the body by combining with and blocking its nervous receptor compare agonist sense 2